iio: light: st_uvis25: Use EXPORT_NS_SIMPLE_DEV_PM_OPS()

Using this new macro removes the need to mark the callbacks
__maybe_unused.  One slightly complexity in this case is that
the export will exist if CONFIG_PM is set, but only be used
if CONFIG_PM_SLEEP is also set. This is harmless.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Link: https://lore.kernel.org/r/20220807185618.1038812-7-jic23@kernel.org


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>